Orthopedic prostheses are commonly utilized to repair and/or replace damaged bone and tissue in the human body. For example, a knee prosthesis used in total knee arthroplasty may include a tibial base plate that is affixed to a resected or natural proximal tibia, a femoral component attached to a resected or natural distal femur, and a tibial bearing component coupled with the tibial base plate and disposed between the base plate and femoral component. Prostheses frequently seek to provide articulation similar to a natural, anatomic articulation of a knee joint, including providing a wide range flexion.
To prepare the relevant bones of the human body to receive prosthesis components, a variety of cutting instruments are sometimes utilized. In the case of the proximal tibia, a bone saw may be utilized to prepare a planar osteotomy of the proximal tibia which is then followed by drilling of the intramedullary canal of the tibia to accommodate a stem extending from the base plate of the stem of the tibial prosthesis. To further shape the tibia to receive the tibial keel, a broach is impacted into the proximal surface of the tibia to create a cavity sized to receive the keel of the tibial prosthesis. After impacting the broach, it must be extracted from the tibia while maintaining the shape of the cavity formed thereby.
When preparing the proximal tibia to receive a tibial prosthesis, instrumentation including a sizing plate may be utilized to facilitate forming a cavity in the tibia sized and shaped to accommodate the stem and keel of a tibial prosthesis that is properly positioned and oriented. The size of the sizing plate corresponds to the size of a prosthesis which is to be mated to the bone. The sizing plate is positioned atop the proximal tibia after the initial, planar osteotomy is performed. Positioning of the sizing plate provides an indication of the location and orientation of the final prosthesis and guides the location of the subsequent bone shaping steps, i.e., drilling and broaching, which are utilized to prepare the bone to receive the tibial prosthesis.